Mount for electron discharge devices



Dec. 29, 1936. K. DREYER 2,065,667,

MOUNT FOR ELECTRON DISCHARGE DEVICES Filed Dec. 1, 1933 'mbeOawa he:

INVENTOR KARL DREYER ATTORNEY Patented Dec. 29, 1936 UNITED S'TTESPATENT OFFICE MOUNT FOR ELECTRON DISCHARGE DEVICES ware ApplicationDecember 1, 1933, Serial No. 700.453

3 Claims.

My invention relates to improvements in electron discharge devices andmore particularly to an improved mount construction by which the mountis resiliently held in position in the bulb.

In radio tubes with the dome type bulb the dome or constricted portionat the top of the tube is utilized to steady the electrode assembly andto keep the assembly from vibrating transversely of the bulb. Aresilient support or brace between the mount and the bulb wall isdesirable in order to prevent noises, such as clicking, caused by theelectrode assembly striking the wall of the bulb when the tube is jarredor vigorously shaken. Metal springs for bracing the mount to the bulbwalls are not feasible as there is a tendency for the glass bulb tocrack, especially during exhaust at those points where the metal touchesit.

One object of my invention is to resiliently support or brace the freeend of an electrode mount from the walls of the bulb by resilient meanswhich engage the walls of the bulb without cracking or otherwiseinjuring the bulb.

The novel features which I believe to be characteristic of my inventionare set forth with particularity in the appended claims, but theinvention itself will best be understood by reference to the followingdescription taken in connection with the accompanying drawing, in whichFigure 1 is a view in perspective and partly broken away of an electrondischarge device embodying my invention;

Figure 2 is an enlarged horizontal cross section along line 2-2 ofFigure 1;

Figure 3 is a View, with the bulb wall section, along the line 33 ofFigure 2;

Figure 4 is a side and edge view of a punched blank from which the micasupporting clip in accordance with my invention is made;

Figure 5 is a view in elevation of a mica spring and its supporting clipattached to it, and

Figure 6 is a side and edge view of a blank for a modification of a micasupporting clip made in accordance with my invention.

The electron discharge device shown in Figure 1 has a bulb II] with adome at the top and the usual stem and press II and the usual base I2 atthe bottom. The electrode assembly I 3 is mounted on the stem II and itsupper end projects into the tubular portion or dome of the bulb I0. Theelectrodes are accurately spaced by a pair of insulating bars, one ateach end of the electrode assembly, such as a bottom mica I4, fastenedto the plate electrode by straps I5, and a top mica I6, located at thetop of the electrode assembly. The upper end of the electrode assemblyis firmlyyet resiliently steadied from the bulb walls by spacers I I ofresilient insulation, such as sheet mica, mounted at the ends of the topmica I6 to rest against the walls of the bulb I0. These strips orspacers are mounted parallel to the vertical axis of the dome of thebulb and lie fiat to the wall, with their ends in contact with the walland their intermediate portions spaced away from the wall.

The fiat mica spacers H are mounted on the upper end of the electrodeassembly by metal clips or supports I8, which, as best shown in Figure4, are conveniently made from blanks punched from sheet metal and foldedalong the dotted lines into the shape shown in Figures 1, 2, and 3.These clips have fingers I9 and 20 which are bent over to grasp the micaspacer I 1 near the middle and hold it in the clip, as shown in Figure5. The mica spacer I! has in its lower edge a recess for the finger 20,which thus prevents the spacer slipping endwise and out of the clip. Theclip has near its ends grooves 2| which form, when the clip is closed, achannel for receiving the upper ends of the plate side rods of theelectrode assembly. The clip blanks also have slots 22 to receive theends of the upper mica I6 when the clips are fastened, preferably bywelding, to the upper end of the electrode assembly, as shown in Figures1, 2, and 3. These slots 22 enable the clips to hold the upper mica I6firmly in place on the electrode assembly, so that straps, such as I5,are not needed to hold the upper mica to the assembly. The clip orsupport I8 is advantageously made of sheet metal, but could be madeintegral with some metal part, such as the plate of the electrodeassembly.

When, during assembly of the tube, the bulb is placed over the electrodeassembly the ends of the mica spring spacers I1 rest against the curvedinner wall of the tubular portion or dome of the bulb I I). Thesespacers, which are secured intermediate their ends to the electrodeassembly, are of such a length that they are, as shown in Figure 2, bentslightly when in the dome, hence they act to resiliently support orbrace the electrode assembly and hold it steady in the bulb. The clipsI6 position the mica spacers accurately with respect to the assembly andthe dome of the bulb and prevent displacement of the spacers duringassembly of the tube. Because of the resiliency of the mica spacers theusual and unavoidable variations in bulb diameter are compensated forand looseness of the electrode assembly in the tube is avoided.

In one form of my invention as embodied in a tube made with a bulbhaving straight sides and a tubular extension or dome and usually knownas STI4, and having a dome about 1.30" in diameter, I have obtained goodresults by using mica spacers I! about .95" long placed about .93 apart,so that their ends rest against the walls of the dome. Mica spacers from8 to 12 mils thick will be sufiiciently resilient to give the desiredresults, and be suificiently flexible to compensate for the unavoidableslight variations in diameter of the bulb.

Figure 6 shows the clip I 8 modified to have spurs or pointedprojections 23 which extend through the mica spacer and are bent over tofasten the spacer in place in the clip. Obviously, the mica spacer maybe fastened to the metal clip in various other ways.

While I have indicated the preferred embodiment of my invention of whichI am now aware and have also indicated specific applications for whichmy invention may be employed, it will be apparent that my invention isnot limited to the exact forms illustrated or the use indicated, butthat many variations may be made in the particular structure used andthe purpose for which it is employed, Without departing from the scopeof my invention as set forth in the appended claims.

What I claim is:

1. An electron discharge device provided with an envelope having atubular portion, a mount comprising an electrode assembly within saidenvelope and extending within said tubular portion, supporting memberssecured to said electrode assembly and provided with a grooved portion,and sheet mica springs engaged intermediate their ends by the groovedportion of said members and set perpendicularly to the transverse axisof the tubular portion of said envelope with their ends in engagementwith the walls of said tubular portion to resiliently and accuratelyposition the mount within the tubular portion of said envelope.

2. An electron discharge device provided with an envelope having atubular portion, a mount comprising an electrode assembly within saidenvelope extending Within said tubular portion, supporting memberscomprising a punched blank folded to provide a flat surface havingprojections thereon and an extension for securing said supportingmembers to the electrode assembly with the flat surface parallel to thelongitudinal axis of said tubular portion, sheet mica springs inengagement with said flat surfaces, the projections on said flatsurfaces being formed to maintain said mica springs in engagement withsaid supporting members and with their ends in engagement with the Wallsof said tubular portion to resiliently support the mount within thetubular portion of said envelope. I

3. An electron discharge device provided wit an envelope having atubular portion, a mount comprising an electrode assembly within saidenvelope extending within said tubular portion, a flat insulating spacerfor said electrode assembly extending transversely of said tubularportion, supporting members having extensions for securing said membersto said electrode assembly, said extensions being provided with a slotfor receiving said insulating spacer to lock said spacer on saidelectrode assembly, mica springs set parallel to the longitudinal axisof the tubular portion of said envelope, and means on said supportingmembers to engage said mica springs intermediate their ends with theends of said mica springs in-engagement with the tubular portion of saidenvelope to resiliently support said mount within said envelope.

KARL DREYER.

